Medical device amenable to fenestration

ABSTRACT

The present invention is directed to a device that permits a permanent aperture to be formed in a wall, or other partition, of an implantable medical device. The present invention maintains the continuity and fluid-retaining properties of the implantable medical device by providing a breachable barrier material fully covering an opening delimited by a deformable framework. The invention is accessed with conventional interventional surgical instruments that disrupt and displace the barrier material. Following disruption of the barrier material, the opening is enlarged with surgical instruments to form a permanent framed aperture in the wall of the implantable medical device. The permanent framed aperture provides fluid communication across the wall of the implantable medical device.

FIELD OF THE INVENTION

[0001] The present invention relates to implantable medical devices.More particularly, the invention relates to means for forming a framedaperture in wall portions, or other partitions, of implantable medicaldevices to establish and maintain fluid communication across the wallportion of the medical device. The present invention also relates tomethods of making the invention.

BACKGROUND OF THE INVENTION

[0002] Abdominal aortic aneurysms (AAAs) and thoracic aortic aneurysms(TAAs) are diagnosed in approximately 250,000 and 20,000 patientsrespectively each year. Left untreated, these aneurysms commonlyprogress to rupture resulting in death. Prior to the advent ofinterventional catheter-based techniques, conventional surgicaltreatment has been the method of treatment for these lesions. Due to theoften emergent condition of these patients and the potential forsignificant blood loss, high morbidity and mortality rates have beenassociated with this type of surgery.

[0003] With the introduction of catheter-based interventionaltechniques, new non-surgical therapies were made available to manypatients. Since the initial animal work performed by Schatz et. al.,small metallic tubes (i.e., stents) have been found to be of significantbenefit for patients with coronary artery and peripheral artery disease.Schatz, R. A., Palmaz, J. C., Tio, F. O., Garcia, F., Garcia, O.,Reuter, S. R. “Balloon-expandable intracoronary stents in the adultdog.” Circulation 76:450-7 (1987). In an effort to treat abdominalaortic aneurysms, Parodi et. al. reported on their experience withcombining the barrier properties of synthetic vascular grafts with stenttechnology (i.e., stent-graft) to effectively inhibit blood flow intothe aneurysm sac using catheter delivery systems. Parodi, J. C., Palmaz,J. C., Barone, H. D. “Transfemoral intraluminal graft implantation forabdominal aortic aneurysms.” Ann. Vasc. Surg 5:491-9 (1991).

[0004] This technology has continued to progress with significantimprovements in successful device deployment and improved patientoutcomes. Despite these improvements, there are many patients for whichthis technology is not applicable as a result of unique anatomical ordisease conditions. Specifically, in the case of AAA disease,stent-graft devices typically require some amount of healthy vessel bothproximal and distal to the aneurysm sac into which to place thestent-graft. In many patients, the proximal vessel is not long enough toachieve adequate fixation. Placement of the stent-graft in a moreproximal location in these patients in order to achieve adequatefixation could partially or completely occlude the renal arteriesproviding blood to the kidneys. A number of different device designshave been proposed to allow device fixation to the aortic vesselproximal to the renal arteries (i.e., suprarenal fixation). Widespreadapplicability of supra-renal fixation devices has been limited by theflexibility of these designs, morphological variation of aneurysmal neckgeometry across patients, and the coverage of the renal ostia withmetallic stents which can act as a nidus for thromo-embolism of therenal circulation and/or hinder subsequent interventional access to thisvasculature.

[0005] A similar situation exists for TAA disease. These aneurysmallesions are often located in close proximity to the subclavian andcarotid arterial branches. When inadequate proximal vascular tissue isavailable for anchoring the endoprosthesis, a suitable proximalanchoring zone can be created by performing a surgical transpositionprior to the interventional procedure. This surgical approach isintended to assure continued flow to all vessels. Alternative means forachieving side-branch perfusion through the wall of a stent-graft aretherefore desirable.

[0006] Other clinical conditions where there would be a benefit forfluid communication through the wall of a prosthesis are those involvingcardiac surgery. Arterial blood leaving the heart serves to carry oxygento the body. In contrast, venous blood is returned to the heart via thesuperior and inferior vena cava after releasing oxygen to the body andabsorbing carbon dioxide and other waste products. Approximately 40,000children are born each year with congenital heart defects. Theseabnormalities often involve a single functional ventricle and defects inthe tissues (i.e., septum) separating the right (venous) and left(arterial) side of the heart. Mixing of arterial and venous blood inthese patients results in reduced oxygen carrying capacity and oftenshortened life expectancies.

[0007] Cardiac surgical interventions performed for the most complexcongenital heart abnormalities often require multiple surgicalprocedures to effect the final treatment for the patient. The Fontanprocedure is an example of a staged surgical treatment that is designedto overcome these significant structural heart abnormalities and isolatesystemic and pulmonary circulation at the definitive treatment.“Correction de I'atresie tricuspidienne.” Fontan, F., Mounicot, F. B.,Baudet, E., Simonneau, J, Gordo, J., Gouffrant, J. M. Rapport de deuxcas “corriges” par I'utilisation d'une technique chirurgicale nouvelle.[“Correction” of tricuspid atresia. 2 cases “corrected” using a newsurgical technic] Ann-Chir-Thorac-Cardiovasc 10:39-47 (1971).Annecchino, F. P., Fontan, F., Chauve, A., Quaegebeur, J. “Palliativereconstruction of the right ventricular outflow tract in tricuspidatresia: a report of 5 patients.” Ann-Thorac-Surg.29:317-21 (1980).Ottenkamp, J., Rohmer, J., Quaegebeur, J. M., Brom, A. G., Fontan, F.“Nine years' experience of physiological correction of tricuspidatresia: long-term results and current surgical approach.” Thorax37:718-26 (1982). The surgical procedures must be staged to minimize thepressure and volume loads on the remaining functional single ventricle.In the first stage procedure, a connection is created between theSuperior Vena Cava (SVC) and the Pulmonary Artery (PA). This is referredto as a Hemi-Fontan or Glenn Shunt procedure. Mathur, M., Glenn, W. W.“Rational approach to the surgical management of tricuspid atresia.”Circulation 37:1162-7 (1968). This shunt reduces the degree of venousand arterial blood mixing, and improves oxygenation of the blood.

[0008] Once the pulmonary circulation and functional ventricle aresufficiently developed, a subsequent procedure is performed wherein theblood going to the right ventricle is bypassed, by routing the blood inthe Inferior Vena Cava (IVC) directly to the PA by way of a baffle ortube connecting the IVC to the PA. At the time of this procedure, asmall hole is typically created in the side of the connection tube toallow some flow of blood into the right ventricle. This small hole isconsidered a temporary connection that reduces the work for theremaining ventricle when pulmonary vascular resistance is elevated.Bridges, N. D., Mayer, J. E., Lock, J. E., Jonas, R. A., Hanley, F. L.,Keane, J. F., Perry, S. B., Castaneda, A. R. “Effect of bafflefenestration on outcome of the modified Fontan operation.” Circulation86:1762-9 (1992).

[0009] The final surgical procedure involves either surgical closure ortranscatheter occlusion of the temporary hole in the IVC to PA connectortube. This multi-staged conventional surgical approach for patients withcomplex congenital heart disease is not optimal as it puts patients atadditional risk of morbidity and mortality with each subsequent surgicalintervention. This risk may be reduced if the first surgicalintervention can set the stage for a future minimally invasive procedurethat eliminates the need for additional open-heart surgery.

[0010] Various devices and design modifications have been proposed in aneffort to provide access to anatomical structures surrounding the deviceor to internal spaces of the device.

[0011] U.S. Pat. No. 6,428,565, issued to Wisselink, and U.S. Pat. No.6,395,018, issued to Castaneda, each relate to stent-graft systems withpre-formed apertures to allow for side-branch access. Neither of thesedevices have apertures that are closed at the time of initial implant.

[0012] U.S. Pat. No. 6,398,803, issued to Layne, et. al., relates topartially covered stents having various patterns of open apertures alongthe length of the device. As with the Wisselink and Castaneda devices,the apertures are fully formed prior to deployment of the device.

[0013] U.S. Pat. No. 6,432,127, issued to Kim, et. al., disclosesformation of an aperture in the wall of a vascular conduit through theuse of a cutting tool. The conduit does not provide a deformableframework encompassing the aperture formation site. As a result,targeting the precise location of the region in which to create theaperture is difficult to visualize using conventional imagingtechniques. Moreover, the aperture is not reinforced along itsperipheral regions once the aperture is formed. The absence of aframework delimiting the aperture formation site precludes precisesizing of the aperture during its formation.

[0014] There remains a need for a device that initially maintains thecontinuity and fluid-retaining properties of a wall portion of animplantable medical device, while providing means for forming apermanent aperture in the medical device. Such a device would permitcustom sizing of the aperture in situ at the implant site duringsurgery.

SUMMARY OF THE INVENTION

[0015] The present invention is directed to a device that is amenable totransmural fenestration. In particular, the present invention permits apermanent framed aperture to be formed in a wall, or similar partition,of implantable medical devices as a means for establishing andmaintaining fluid communication across the wall of the medical devicefollowing implantation. The present invention provides a breachablebarrier material that initially maintains the continuity and anyfluid-retaining properties of the wall of the medical device. Thebreachable barrier material fully covers an opening delimited by aframework. In use, the breachable barrier material is breached with asurgical instrument and the shape of the framework altered to enlarge,or otherwise alter, the area of the opening. In the process, the openingbecomes uncovered and accessible to flow of fluid through the opening.The altered framework provides structural reinforcement to peripheralregions (e.g., circumferential) of the enlarged opening and forms apermanent aperture in the wall of the medical device. The alteredframework can also be used to provide a secure anchoring site forancillary medical devices. The permanent aperture can be formed in thewall of the implantable medical device at the time of surgical orcatheter-based intervention or at a later date through the use ofinterventional or surgical techniques.

[0016] The present invention is particularly suited for use withvascular prostheses, and other implantable medical devices providingfluid containment or fluid partitioning, that can benefit from theformation of one or more permanent apertures in the devices at theimplantation site. With stent-grafts spanning an aneurysm, for example,the invention can provide a framed aperture in the wall of thestent-graft for side-branches or drainage sites. Vascular grafts can bebypassed or bifurcated in-situ with the present invention. The inventioncan also be used with surgically implanted cardiovascular patches toprovide perfusion or other access to the heart and vascular system.

[0017] The present invention can be added to an implantable medicaldevice following its construction, or included in the manufacture of thedevice as an integral component. The breachable barrier material of thepresent invention is made of implantable polymers that are readilybreached, perforated, or otherwise structurally disrupted with surgicalinstruments. The breachable barrier material can also be made ofpolymers that are structurally disrupted through degradation andabsorption by the body of the implant recipient. The polymers of thebreachable barrier material can be incorporated with filler materials toassist in breaching the barrier material or to facilitate visualizationof the aperture region in an implant recipient.

[0018] The framework is made of implantable metallic or polymericmaterials that can be altered in shape. These framework materials can bedeformed or otherwise altered in shape with surgical instruments or haveshape-memory properties that permit the framework to assume differentshapes without the use of an instrument. The framework materials areshaped in various ways to assist in the combined roles of structurallyreinforcing the breachable barrier material and the opening, beingcapable of reconfiguration, and providing a permanent framed aperture.

[0019] In one surgical method, an implantable medical device utilizingthe present invention is placed at a surgical site with conventional orinterventional surgical techniques. Once the correct position of themedical device is confirmed, a catheter guide-wire, or other surgicalinstrument, is used to breach the breachable barrier material and beginto uncover the covered opening. An expandable balloon catheter in adeflated configuration is then inserted into the partially uncoveredopening and inflated. As the balloon catheter is inflated, it expands indiameter, altering the shape of the framework and displacing theremaining barrier material from the area of the opening. When theframework has been reconfigured as desired, the balloon catheter isdeflated and removed from the opening. This leaves a permanent framedaperture in the wall of the medical device. The permanent aperture canprovide immediate therapies and surgical remedies, such as branch vesselperfusion, or co-operate with other medical devices.

[0020] In one embodiment, the present invention is an implantablemedical device comprising a framework delimiting an opening having afirst area and a breachable barrier material fully covering saidopening, wherein a permanent aperture having a second area is formedfollowing breach of said breachable material and said framework isadaptable to be altered in shape.

[0021] In another embodiment, the present invention is an implantablemedical device comprising a continuous wall, at least one framework insaid wall delimiting an opening having a first area, a breachablebarrier material fully covering said opening, wherein a permanentaperture having a second area is formed following breach of saidbreachable material and said framework is adaptable to be altered inshape and have a reinforced peripheral region in said continuous wall.

[0022] Further aspects and advantages of the present invention will beapparent to those skilled in the art after reading and understanding thedetailed description of preferred embodiments set forth hereinbelow andafter viewing the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The foregoing summary, as well as the following detaileddescription of a preferred embodiment of the invention, will be betterunderstood when read in conjunction with the appended drawings. Forpurposes of illustrating the invention, there is shown in the drawingsan embodiment that is presently preferred. It should be understood,however, that the invention is not limited to the precise arrangementand instrumentality shown. In the drawings:

[0024]FIG. 1A illustrates a top view of the present invention.

[0025] FIGS. 1B-1D illustrate a side view of the present invention.

[0026] FIGS. 2A-2E illustrate the present invention in operation.

[0027]FIG. 3A illustrates an embodiment of the present inventionincorporated into a wall of a tubular medical device.

[0028]FIG. 3B illustrates an embodiment of the present inventionincorporated into a planar material that is attached to a wall of atubular medical device.

[0029]FIG. 4 illustrates an embodiment of the present inventionincorporated into a medical device.

[0030]FIG. 4A illustrates an embodiment of the present invention placedin a discrete location relative to scaffolding and wall elements of animplantable medical device.

[0031]FIG. 5 illustrates an abdominal aortic aneurysm.

[0032]FIG. 6 illustrates a stent-graft incorporating an embodiment ofthe present invention placed in the region of an abdominal aorticaneurysm.

[0033] FIGS. 7A-7D illustrate the present invention being utilized toprovide perfusion to side branches of a blood vessel.

[0034]FIG. 7E illustrates an embodiment of the present invention servingas attachment means for another medical device.

[0035] FIGS. 8A-8C illustrate the framework component of the presentinvention in various non-limiting shapes.

[0036]FIG. 9 illustrates the framework component of the presentinvention in the form of an array.

[0037]FIG. 10 illustrates the framework component of the presentinvention in the form of an array.

[0038]FIG. 11 illustrates a method of constructing the breachablebarrier material in an embodiment of the present invention.

[0039]FIG. 12 is an exploded view of an embodiment of the presentinvention under construction.

[0040]FIG. 13 is a perspective view of an embodiment of the presentinvention.

[0041] The accompanying diagrams include various anatomical structuresand associated clinical pathologies that are identified as follows:

[0042] AA=Abdominal Aorta

[0043] RA=Renal Artery

[0044] IA=Iliac Artery

[0045] AAA=Abdominal Aortic Aneurysm

DETAILED DESCRIPTION OF THE INVENTION

[0046] The present invention can be used in combination with a varietyof implantable fluid-containing medical devices to establish fluidcommunication across a wall, or other partition, in the devices. In manysituations, the present invention is employed at the time the medicaldevice is implanted. In other instances, the present invention isaccessed and utilized after the medical device has been implanted for aperiod of time. The present invention can also be used before theimplant procedure begins.

[0047]FIG. 1A is a top view of an embodiment of the present invention 10incorporated into an implantable patch material 12. FIG. 1B is a sideview of this embodiment generally illustrating the relationship of thecomponents. In this embodiment, a framework 14 is surrounded by a layerof implantable polymeric material 18. The framework 14 delimits anopening 16 that is fully covered with a breachable barrier material 17.The polymer layer 18 is sandwiched between two layers of implantablepatch material 12, 13 so as to reveal the framework 14, opening 16, andbreachable barrier material 17 of the present invention. In similarembodiments of the present invention, the implantable patch material orother wall components are considered part of the invention. In additionto implantable medical devices having planar configurations, implantablemedical devices having tubular configurations are also suitable for usewith the present invention. Tubular medical devices are generallycylindrical in shape and not confined to having parallel walls. Inaddition, tubular medical devices have geometries with at least oneinlet and at least one outlet.

[0048] The shape of the framework 14 is chosen to provide structuralsupport to the breachable barrier material 17 while it fully coversopening 16. The shape and composition of the framework also allows theframework to be readily deformed and displaced to peripheral regions ofthe opening to form a permanent framed aperture. The particular shape ofthe framework illustrated in FIG. 1A, et. al., is preferred but notlimiting. For example, FIGS. 8B and 8C illustrate frameworks havingcircular configurations 70 incorporating varying numbers of peaks 76 andvalleys 78. It is also contemplated in the present invention that thedistance between the peaks 76 and valleys 78 (i.e., amplitude) can bevaried broadly, thereby enabling a wide range of framework geometries tobe formed. In addition to enhancing support for the breachable barriermaterial with these framework designs, a wide range of aperture sizescan be achieved with these designs. Supporting leg struts 74 can also beincorporated into the framework design to enhance attachment tosurrounding wall materials. Other non-circular configurations 79 of theframework 14 are also contemplated. Furthermore, FIGS. 9 and 10illustrate that the framework can be in the form of an array ofopenings. These embodiments provide a choice of locations for the framedaperture as well as the number of framed apertures.

[0049] FIGS. 2A-2E illustrate the construct of FIGS. 1A and 1B in use.FIG. 2A is a perspective view of the construct as it might appear at animplantation site. FIG. 2B shows a guide wire 20 from a catheter, orother device, having penetrated and breached the breachable barriermaterial 17. FIG. 2C depicts an expandable balloon catheter 22 in adeflated state being introduced through the breached barrier materialinto opening 16 with guide wire 20. FIG. 2D illustrates inflation of theexpandable balloon catheter 22 and deformation of framework 14. As theframework 14 is deformed, opening 16 is enlarged and expanded in area.Following deflation and removal of the balloon catheter, FIG. 2E showsthe resulting permanent aperture 24 framed with altered framework 14 inimplantable patch material 12.

[0050]FIG. 3A illustrates the present invention 15 as a component of atubular vascular graft 30. In this embodiment, framework 14 delimitingopening 16 is fully covered by breachable barrier material 17 andincorporated into wall portion 32 of vascular graft 30. When theinvention is operated, fluid communication across wall portion 32 toluminal space 34 is established.

[0051]FIG. 3B illustrates an embodiment of the present invention 19having an implantable patch material 11 component. The implantable patchmaterial is attached to an implantable vascular prosthesis 30 by sewing.Other suitable means of attaching the present invention to a wall of animplantable medical device include, but are not limited to, adhering,ultrasonic or radio frequency welding, lamination, stapling, andcovering the medical device with a membrane or film to include thepresent invention.

[0052]FIG. 4 illustrates an embodiment of the present invention 44incorporated into an implantable tubular endovascular device 40. In thisembodiment, the endovascular device 40 is a bifurcated design commonlyused to treat aortic aneurysms and includes a main body, or trunk,portion 50 and two leg portions 52, 54. The endovascular device has astent frame 42 and wall means 48. Several fully covered frameworkelements of the present invention are incorporated into the wall means48 of the stent-graft 40. As seen in FIG. 4, there is a longitudinaldisplacement between the present invention and the support elements(i.e., scaffolding) of the stent-graft. This embodiment of the presentinvention provides multiple sites for forming side branches instent-grafts and other endovascular devices as means for providingselective perfusion and/or drainage of the implantation site.

[0053] In embodiments of the present invention used in combination withstent-grafts, and other implantable medical devices utilizing supportelements (i.e., scaffolding), the framework component of the presentinvention is preferably incorporated into the device separately from thesupport elements. As shown in FIG. 4A, the framework of the presentinvention underlies and is discrete from the support elements of theimplantable medical device. The location of the present invention is notlimited to contact or close proximity to support elements or wallcomponents of an implantable medical device. Indeed, the presentinvention can be positioned in any desired location in an implantablemedical device.

[0054] A clinical application of the embodiment illustrated in FIG. 4 isdepicted in FIGS. 5 and 6. A typical abdominal aortic aneurysm (AAA) isshown in FIG. 5 with the proximal aorta (AA) leading to renal artery(RA) branches and distal iliac arteries (IAs). In cases where thedisease condition or aortic anatomy does not provide sufficient healthyvessel upon which to achieve device fixation at implant, it is oftennecessary to utilize the AA segment proximal to the RAs. In thissuprarenal implant position, an appropriate stent-graft 40 fixation canbe achieved and effective AAA exclusion as shown in FIG. 6. In thisconfiguration however, the barrier properties of the stent-graft wall 48occlude blood flow to the branching RA on both sides. In order toachieve RA perfusion, one or more units 44 of the present invention areselected and utilized.

[0055] The interventional procedure required to access and operate thepresent invention is illustrated in FIGS. 7A-7D. Following deployment ofstent graft 40, a guide catheter 36 is positioned under fluoroscopicguidance to direct a guide-wire 20 toward the center of one of theplurality of available inventions 44 that is in appropriate alignmentwith the RA. Following guide-wire 20 breach of the breachable barriermaterial 16, the framework 14 is altered in shape to the desiredaperture size using a balloon catheter 22. Further inflation of theballoon 22 achieves the desired deformation of the framework 14 andformation of a permanent framed aperture 64 having a size appropriatefor the RA. Once formed, the permanent framed aperture 64 provides forRA blood perfusion 62 in accordance with normal AA blood flow 60.

[0056] The present invention can be constructed of a variety ofimplantable materials. The breachable barrier material has acomposition, structure, and/or thickness sufficient to at leastpartially bar liquids, including blood and other physiological fluids,from crossing the material, yet have sufficient structural weakness tobe readily breached, perforated, or otherwise structurally disruptedwith surgical instruments, or the like. The breachable barrier materialcan be made of non-biodegradable polymers, bio-degradable polymers, andelastomers, either alone or in combination. Elastomers in the breachablebarrier materials can augment uncovering of the fully covered openingfollowing breach of the barrier material. The breachable barriermaterial can be provided with filler materials that also augmentbreaching of the barrier material or assist in locating the invention atan implantation site.

[0057] Suitable surgical instruments or tools for use in breaching thebarrier material at an implantation site include, but are not limitedto, guide-wires, Colapinto® needles, Rotablators®, and other ablationinstruments utilizing radio-frequency energy, ultrasonic sound,microwave energy, or laser light.

[0058] Suitable non-biodegradable polymers include, but are not limitedto, polyester, polytetrafluoroethylene, polyamide, and polyurethane. Thepreferred material for the breachable barrier material is a porousexpanded, or stretched, polytetrafluoroethylene material. Suitablebio-degradable polymers include, but are not limited to, materials madeof polymers or copolymers possessing one or more of the followingmonomeric components: glycolide (glycolic acid); lactide (d-lactide,I-lactide, d,I-lactide); trimethylene carbonate; p-dioxanone;caprolactone, and hydroxybutyrate, hydroxyvalerate. Elastomericmaterials suitable for use in the present invention include, but are notlimited to, fluoroelastomers, polyurethane. Suitable filler materialsfor incorporation into the breachable barrier material include, but arenot limited to, graphite, titanium oxide (TiO), barium, vitamin E,gadolinium, lossy materials, and other radio-opaque compositions.

[0059] The breachable barrier material can be applied to the frameworkas a single layer or in multiple layers. When using multiple layers ofbreachable barrier material, it is preferred to orient the individuallayers in different directions (see e.g. FIG. 11).

[0060] The framework is made of materials that are capable of supportingthe breachable barrier material while the barrier material is fullycovering the opening delimited by the framework. The materials of theframework permit the framework to be readily shaped, reshaped, orotherwise altered in configuration while the invention is located at animplantation site. The framework can be made of malleable materials,plastically deformable materials, and/or self-expanding (i.e.,super-elastic) metals or polymers. When materials are used that do notlend themselves to visualization with fluoroscopy, x-ray imagining,magnetic resonance imaging, etc., radio-opaque or other imagingcompounds can be introduced into the framework materials.

[0061] The materials of the framework also need to be sufficientlyresilient to provide permanent reinforcement of peripheral regions ofthe aperture under physiological conditions. In addition to providingstructural support to peripheral regions of the aperture portion of theinvention, the framework component can serve as anchoring means forother medical devices 90 attached thereto (e.g., FIG. 7E).

[0062] Suitable materials for the framework include, but are not limitedto, implantable metals such as gold, silver, tantalum, tungsten, andchromium, implantable metal alloys such as stainless steel, nitinolmetal, and implantable polymers such as polyurethanes, fluorinatedethylene propylene, and polytetrafluoroethylene. The framework can bemade by molding, casting, laser cutting and/or laser machining,stamping, photo-etching, wire-forming, electrical discharge machining(EDM), bent wire techniques, or other suitable fabrication method.

[0063] In embodiments of the present invention that include a patch,tube, or other walled component, essentially any implantable materialcan be used for the component. Suitable materials include but are notlimited to, implantable metals, implantable metal alloys, implantablepolymers such as polyester (Dacron®), polyamide (Nylon),polytetrafluoroethylene, silicone, and polyurethane.

[0064] The present invention can be constructed in a variety of ways.The invention can be made by attaching the breachable barrier materialto the framework material with adhesives, heat, pressure, and/orultrasonic welding. In turn, the breachable barrier material can beattached to an implantable medical device with similar methodologies.The invention can also be incorporated into an implantable medicaldevice by molding, sewing, wrapping with a film or membrane, and/ormechanical fixation.

[0065] An implantable medical device made of an expandedpolytetrafluoroethylene (ePTFE) in the form of a tube or sheet can besupplied with an embodiment of the present invention by first cutting ahole in the ePTFE slightly smaller than the largest diameter of theframework component. Next, a powder coating of fluorinated ethylenepropylene (FEP) is applied to both sides of the framework material andthe framework material placed over the hole in the ePTFE material. Asuitably sized piece of breachable barrier material is placed over theframework component. Heat and pressure are applied to the combination toattach the materials together.

[0066] Another method of attaching the present invention to animplantable medical device involves applying an adhesive material, sucha room temperature vulcanizing (RTV) silicone, to both sides of theframework material and pressing one side of the framework onto a wall ofthe medical device having a suitably sized hole formed therein. Asuitable breachable barrier material is then pressed onto the otheradhesive-coated side of the framework component. Any excess barriermaterial is trimmed away from the framework to complete theinstallation.

[0067] Yet another method of attaching the present invention to animplantable medical device involves placing a framework component over asuitably sized hole in a wall of the medical device and wrapping one ormore layers of a biocompatible film over the framework component. Inthis embodiment, the wrapped film layer(s) can also serve as thebreachable barrier material. The film wrapping material can be furthersecured by heating the construction.

[0068] For implantable medical devices having a wall element in the formof a meshwork, the present invention can be attached to the medicaldevice in such a way that the opening is accessibly through holes in themeshwork. In this embodiment, an adhesive-coated framework material isplaced on a breachable barrier material. Additional adhesive is placedon perimeter regions of the barrier material. A meshwork device isplaced over this combination so the opening of the present invention isaccessible through one or more holes in the meshwork. Pressure isapplied to the construct to adhere the components together. A preferredimplantable medical device is a woven mesh material commerciallyavailable from Davol, Inc. under the trade name Bard® Marlex™Mesh—Monofilament Knitted Polypropylene (Catalog No. 011265).

[0069] These construction methodologies are exemplary and are notintended to limit the scope of the present invention.

EXAMPLES

[0070] Without intending to limit the scope of the present invention,the apparatus and method of production of the present invention may bebetter understood by referring to the following examples.

Example 1

[0071] A planar sheet embodiment of the present invention, approximately8.3 cm (3.25″) by 13.3 cm (5.25″), was constructed as follows. A firstlayer of an expanded polytetrafluoroethylene (ePTFE) sheet materialhaving a thickness of about 0.4 mm was obtained from the MedicalProducts Division of W. L. Gore & Associates, Inc., Flagstaff, Ariz.under the tradename GORE-TEX® Cardiovascular Patch as part number1800610004 (FIG. 12, part A1).

[0072] A second layer of a fluoro-elastomeric sheet material composed ofa thermoplastic copolymer of tetrafluoroethylene (TFE) andperfluoro(methyl vinyl ether) (PMVE) was constructed by compressionmolding the crumb form of the copolymer at a temperature of about 250°C. to form a sheet about 0.2 mm (0.008″) in thickness (FIG. 12, partA3). The resulting material had the attributes described in TABLE 1below.

[0073] A third layer of sheet material (FIG. 12, part A4) is composed ofePTFE made according to U.S. Pat. No. 4,482,516, issued to Gore. Thesheet material was approximately 0.17 mm thick with an average fibrillength of greater than about 10 microns.

[0074] A sheet of medical grade 316 stainless steel was obtained fromLaserage Technologies, Inc., Waukegan, Ill. for use in constructing aframework. The framework was laser machined into an undulating patternhaving a continuous, generally circular, ringed configuration (FIG. 12,part A2). The thickness of the framework was about 0.4 mm (0.016″). Theminimum distance between individual framework elements located oppositeone another in the opening delimited by the framework was about 0.2 mm(0.008″).

[0075] These four components were aligned together as shown in FIG. 12.Components 100, 102, 103, and 104 were placed between layers of hightemperature padding material and aluminum plates (FIG. 12, parts 105,106). The aluminum plates were approximately 15.2 cm (6″) square and0.062″ thick. The high temperature padding material 105 was made ofGORE-TEX® Soft Tissue Patch having a thickness of about 2 mm (0.079″)available from the Medical Products Division of W. L. Gore & Associates,Inc., Flagstaff, Ariz. as part number 1310015020. The assembly wasplaced in a heated Carver press and laminated together in thearrangement shown in FIG. 12 for about 5 minutes, at about 200° C. witha pressure of about 0.5 Mpa (80 lb/in²). Following the compression cyclein the press, the padding material was discarded.

[0076] A 4 mm hole was then cut though all three layers of material atthe center point of the reinforcement element using a 4 mm sharpenedcoring punch. Four layers of high strength ePTFE film made according toU.S. Pat. No. 5,476,589, issued to Bacino, were obtained and oriented at90 degree angles with respect to one another (Figure C). A layer ofdiscontinuous fluorinated ethylene propylene (FEP) coating was placedbetween each layer of ePTFE material. These combined materials wereplaced over the cutout hole and secured in place using a heatedsoldering iron applied around the outer perimeter of the cutout hole.Excess film material was than trimmed from the final assembly and theedges tacked down thoroughly with the heated soldering iron. Theresulting article is shown in FIG. 13. TABLE 1 Characteristic TargetPMVE wt % about 60% TFE wt % About 40% 100% Secant Modulus* About2.1-2.2 MPa Softening Temperature <275° C. Thermal DegradationTemp. >300° C. Melt Flow Index** >2.0 Durometer 60-80 Shore A

Example 2

[0077] This example describes a tubular vascular graft having thearticle of Example 1 incorporated into the wall of the tubular graft.The article of Example 1 was trimmed and sewn into a corresponding holecut through the wall of an ePTFE vascular graft. The ePTFE vasculargraft was a GORE-TEX® Vascular Graft available from the Medical ProductsDivision of W. L. Gore & Associates, Inc., Flagstaff, Ariz. as partnumber SA1604. The article from Example 1 was sewn into thecorresponding hole of the tubular construct with an ePTFE suturematerial obtained from Medical Products Division of W. L. Gore &Associates, Inc. Flagstaff, Ariz. under the tradename GORE-TEX® Sutureas part number CV-5. The resulting article is shown in FIG. 3B.

[0078] Accurate and illustrative examples of the invention have beendescribed in detail however, it is readily foreseen that numerousmodifications may be made to these examples without departing from thenature and spirit or scope of the present invention.

We claim:
 1. An implantable medical device comprising a frameworkdelimiting an opening having a first area and a breachable barriermaterial fully covering said opening, wherein a permanent aperturehaving a second area is formed following breach of said breachablematerial and said framework is adaptable to be altered in shape.
 2. Theimplantable medical device of claim 1 wherein said framework isincorporated into a medical device.
 3. The implantable medical device ofclaim 2 wherein said medical device is a vascular prosthesis.
 4. Theimplantable medical device of claim 4 wherein said vascular prosthesisis a vascular graft.
 5. The implantable medical device of claim 4wherein said vascular prosthesis is a stent-graft.
 6. The implantablemedical device of claim 5 wherein said device is distinct from supportelements of said stent-graft.
 7. The implantable medical device of claim4 wherein said vascular prosthesis is a surgical patch.
 8. Theimplantable medical device of claim 1 wherein said breachable barriermaterial comprises a fluoropolymer.
 9. The implantable medical device ofclaim 8 wherein said fluoropolymer is a polytetrafluoroethylenematerial.
 10. The implantable medical device of claim 1 wherein saidbreachable barrier material comprises a bio-degradable material.
 11. Theimplantable medical device of claim 1 wherein said breachable barriermaterial includes a filler material.
 12. The implantable medical deviceof claim 1 wherein said breachable barrier material comprises anelastomer.
 13. The implantable medical device of claim 1 wherein saidframework is made of an implantable metal.
 14. The implantable medicaldevice of claim 1 wherein said framework is made of an implantablepolymer.
 15. An implantable medical device comprising a continuous wall,at least one framework in said wall delimiting an opening having a firstarea, a breachable barrier material fully covering said opening, whereina permanent aperture having a second area is formed following breach ofsaid breachable material and said framework is adaptable to be alteredin shape and have a reinforced peripheral region in said continuouswall.
 16. The implantable medical device of claim 15 wherein saidcontinuous wall has a planar geometry.
 17. The implantable medicaldevice of claim 15 wherein said continuous wall has a tubular geometry.18. The implantable medical device of claim 15 wherein said continuouswall is a vascular prosthesis.
 19. The implantable medical device ofclaim 18 wherein said vascular prosthesis is a vascular graft.
 20. Theimplantable medical device of claim 18 wherein said vascular prosthesisis a surgical patch.
 21. The implantable medical device of claim 18wherein said vascular prosthesis is a stent-graft.
 22. The implantablemedical device of claim 21 wherein said device is distinct from supportelements of said stent-graft.
 23. The implantable medical device ofclaim 15 wherein said device is a component of a vascular prosthesis.24. The implantable medical device of claim 23 wherein said vascularprosthesis is a stent-graft.
 25. The implantable medical device of claim24 wherein said device is distinct from support elements of saidstent-graft.
 26. The implantable medical device of claim 15 wherein saidcontinuous wall comprises a fluoropolymer.
 27. The implantable medicaldevice of claim 26 wherein said fluoropolymer is apolytetrafluoroethylene material.
 28. The implantable medical device ofclaim 15 wherein said framework is made of an implantable metal.
 29. Theimplantable medical device of claim 15 wherein said breachable barriermaterial comprises a fluoropolymer.
 30. The implantable medical deviceof claim 29 wherein said fluoropolymer is a polytetrafluoroethylenematerial.
 31. The implantable medical device of claim 15 wherein saidbreachable barrier material comprises a biodegradable material.
 32. Theimplantable medical device of claim 15 wherein said breachable barriermaterial includes a filler material.
 33. The implantable medical deviceof claim 15 wherein said breachable barrier material comprises anelastomer.